An American held for two years by a terror group in Syria is free tonight. As his family celebrates, however, the family of James Foley, executed on video by another terror group, Isis, held a memorial service today. Meanwhile, president Obama is returning to Washington from vacation with a big decision to make about Isis, and ABC's Jon Karl is with him on Martha's vineyard. Reporter: Dan, the president heads back to the white house tonight after receiving a rare bit of good news out of Syria. My name is peter Theo Curtis. Reporter: Peter Theo Curtis had been held hostage by terrorists in Syria for nearly two years. Now he is finally free. Originally from Massachusetts Curtis is a 45-year-old writer who also goes by the name Theo padnos and has spent the last several years in Syria and elsewhere in the middle east held by an Al Qaeda linked group known as Al nusrah. This is a different group from Isis which killed James Foley. Secretary of state John Kerry said the U.S. Had worked with more than two dozen countries over the past two years to get him freed. His family said no ransom was paid. ? meanwhile, in New Hampshire, a memorial for Jim Foley. Friends and family gathered to remember the journalist brutally murdered by Isis and called a hero by president Obama, and while U.S. Warplanes hit more Isis targets in Iraq today, the terror group scored another big victory in Syria capturing a major air base from the Syrian government. Another reason defeating Isis means fighting them in Syria as well as Iraq. As the former top U.S. Commander in Afghanistan told George stephanopoulos today. It's going to require a comprehensive approach to strike Isis throughout the entire network of its organization. On top of the president's agenda back in Washington, a big decision about whether to expand air strikes to targets in Syria. White house officials say the president will consult with congress on that, but they do not believe that he needs congressional approval to hit terrorist targets in Syria. Dan? A major decision looming for this president. Jon Karl, thank you.

This transcript has been automatically generated and may not be 100% accurate.

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